1. Field of the Invention
The invention relates to the oxidation or halogenation of hydrocarbons by a process termed electrogenerative wherein the free energy of reaction is partially converted directly into potentially useful electric energy while the main product of value is produced.
2. Description of the Prior Art
The halogenation of hydrocarbons, for instance the chlorination of ethylene to produce 1,2-dichloroethane is carried out in a chemical method by reacting anhydrous ethylene saturated with ferric chloride at a temperature of 50.degree. centigrade. The yield of 1,2-dichloroethane (calculated for chlorine reacted) approaches 100%. The chemical method for preparing 1,2-dichloroethane involves a preliminary production of chlorine, a subsequent purification thereof, compression and thorough drying of the chlorine since moisture impairs the process parameters by inactivating ferric chloride which is required to inhibit the substitutive chlorination of ethylene.
Also known is a method for preparing 1,2-dichloroethane utilizing an electrolysis cell containing about 4% to about 20% aqueous hydrochloric acid as an electrolyte at a temperature between 20.degree. to 70.degree. centigrade with the simultaneous supply of ethylene into the anodic space. A combination of ethylene and aqueous hydrochloric acid is fed into the anodic space at such a rate that the amount of hydrochloric acid fed into the solution is ten times higher than its stoichiometric amount. The current yield of 1,2-dichloroethane is 20% to 44%. This is equivalent to the yield calculated based upon reacted chlorine in the chemical method.
Prior art methods of electrogenerative halogenation of hydrocarbons are discussed in a thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy by Miller at the University of Wisconsin (1973). Electrolytic oxidation and chlorination of ethylene are discussed by Kalinin et al in Journal of Applied Chemistry, 19, No. 10-11, 1045-1058 (Russian) (1946). Electrogenerative processes are disclosed by Langer et al in Industrial Engineering Chemistry and Process Design Development, 18 No. 4 (1979) pages 567 to 579 and in Langer et al Journal of The Electrochemical Society pages 510-511, April 1970. A flow through electrochemical cell is disclosed in Kinoshita and Leach in the Journal of The Electrochemical Society 129 No. 9, pages 1993-1997 (September 1982).
In none of these references is the applicant's novel flow through electrogenerative cell or process for the oxidation or halogenation of hydrocarbons disclosed.